Structural Geology

My engagement in structural geology stemmed primarily from that fact that I spent a number of summers in the 70’s and early 80’s mapping for the Maine Geological Survey on Nuclear Regulatory Commission funding. These projects followed three seismic hot spots, namely the Passamaquoddy Bay area in eastern Maine, the central Maine seismic zone, and the area north of the Chain Lakes Massif on the western Maine border with Canada.

Coming to Vermont in 1982 brought with it a second survey stint, this time with the Vermont Geological Survey, during which my focus was on mapping the Northfield 7.5-minute quadrangle (WestermanNorthfieldQuad), again with a strong structural bent to the work since the quadrangle contained the zone separating western and eastern Vermont geology. This boundary, long thought to be an erosional unconformity between Cambro-Ordovician terrane to the west and Siluro-Devonian terrane to the east, was referred to by New England mappers as the RMC (Richardson Memorial Contact), later named the Taconian Line by Hatch. My detailed mapping along the boundary consistently revealed fault structures across a half-mile wide zone for which I coined the name Dog River Fault Zone, which I then traced north to the Canadian border and south as far as Randolph, VT.

My detailed mapping in Vermont slowed considerably once I started working each summer in the Tuscan Magmatic Province. These studies, led by Fabrizio Innocenti of Pisa, were primarily research in igneous petrology, but like all good field studies, they’re riddled with structural evidence. This was most powerfully evidenced in the Elba work where unraveling the igneous history required extensive reconstruction of the geology by undoing thrust faults and normal faults associated with the emplacement of the nested Christmas-tree laccolith complex, the Monte Capanne plutonic sheets, and extensive Orano dike system.

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